Hello, After updating to the latest main (at eda130f3bf1c), in our team we've noticed, that in our CI, that QMI port sometimes fails to probe, with Telit LE910C4-WWXD. The result is the modem having only AT ports available, thus falling back to using PPP for the data connection.
I've bisected ModemManager's source code from previous update, which was
working OK, and narrowed down the issue to the following commit:
ed13e053cd42 ("port-probe: fix custom init probing not having open AT port").
Reverting it for testing fixes the issue.
I haven't yet dug to the root cause fully, but since current main branch is
affected, I decided to reach out early.
The debug logs show, that probe fails right after first QMI transaction, and
usbmon capture (attached) confirms that:
ModemManager[13321]: <DEBUG> <dbg> [1734028733.422964] [/dev/cdc-wdm0] sent
message...#012<<<<<< RAW:#012<<<<<< length = 28#012<<<<<< data =
01:1B:00:00:00:00:00:01:00:FF:10:00...#012
ModemManager[13321]: <DEBUG> <dbg> [1734028733.423671] [/dev/cdc-wdm0] sent
generic request (translated)...#012<<<<<< QMUX:#012<<<<<< length =
27#012<<<<<< flags = 0x00#012<<<<<< service = "ctl"#012<<<<<< client =
0#012<<<<<< QMI:#012<<<<<< flags = "none"#012<<<<<< transaction =
1#012<<<<<< tlv_length = 16#012<<<<<< message = "Internal Proxy Open"
(0xFF00)#012<<<<<< TLV:#012<<<<<< type = "Device Path" (0x01)#012<<<<<<
length = 13#012<<<<<< value =
2F:64:65:76:2F:63:64:63:2D:77:64:6D:30#012<<<<<< translated =
/dev/cdc-wdm0#012
ModemManager[13321]: <DEBUG> <dbg> [1734028733.429528] [/dev/cdc-wdm0]
received message...#012<<<<<< RAW:#012<<<<<< length = 19#012<<<<<< data =
01:12:00:80:00:00:01:01:00:FF:07:00...#012
ModemManager[13321]: <DEBUG> <dbg> [1734028733.430244] [/dev/cdc-wdm0]
received generic response (translated)...#012<<<<<< QMUX:#012<<<<<< length =
18#012<<<<<< flags = 0x80#012<<<<<< service = "ctl"#012<<<<<< client =
0#012<<<<<< QMI:#012<<<<<< flags = "response"#012<<<<<< transaction =
1#012<<<<<< tlv_length = 7#012<<<<<< message = "Internal Proxy Open"
(0xFF00)#012<<<<<< TLV:#012<<<<<< type = "Result" (0x02)#012<<<<<<
length = 4#012<<<<<< value = 00:00:00:00#012<<<<<< translated =
SUCCESS#012
ModemManager[13321]: <DEBUG> <dbg> [1734028733.430446] [/dev/cdc-wdm0]
checking version info (45 retries)...
ModemManager[13321]: <DEBUG> <dbg> [1734028733.430596] [/dev/cdc-wdm0] sent
message...#012<<<<<< RAW:#012<<<<<< length = 12#012<<<<<< data =
01:0B:00:00:00:00:00:02:21:00:00:00...#012
ModemManager[13321]: <DEBUG> <dbg> [1734028733.430673] [/dev/cdc-wdm0] sent
generic request (translated)...#012<<<<<< QMUX:#012<<<<<< length =
11#012<<<<<< flags = 0x00#012<<<<<< service = "ctl"#012<<<<<< client =
0#012<<<<<< QMI:#012<<<<<< flags = "none"#012<<<<<< transaction =
2#012<<<<<< tlv_length = 0#012<<<<<< message = "Get Version Info"
(0x0021)#012
ModemManager[13321]: <DEBUG> <dbg> [1734028733.434635] [cdc-wdm0/at] <--
'\1\197\0\128\0\0\1\1!\0\186\0\2\4\0\0\0\0\0\1\176\0#\0\1\0\5\0\1\1\0C\0\2\1\0\0\0\3\1\0\25\0\4\1\0\12\0\5\1\0<LF>\0\7\1\0\3\0\8\1\0\4\0\9\2\0\1\0<LF>\2\0\24\0\11\1\0W\0\12\1\0\4\0\15\1\0\0\0\16\2\0\0\0\17\1\0\0\0\18\1\0\0\0\20\1\0\0\0\23\1\0\0\0\24\1\0\0\0\26\1\0\16\0\29\1\0\1\0\31\1\0\0\0!\1\0\0\0"\1\0\0\0$\1\0\0\0)\1\0\0\0*\1\0\0\00\1\0\0\02\1\0\0\06\1\0\0\0I\1\0\0\0\231\1\0\0\0\232\1\0\0\0\235\1\0\0\0\237\1\0\0\0'
ModemManager[13321]: <WARNING> <wrn> [1734028733.435136] Cannot read from
istream: connection broken
ModemManager[13321]: <DEBUG> <dbg> [1734028733.435205] [/dev/cdc-wdm0]
endpoint hangup: removed
ModemManager[13321]: <DEBUG> <dbg> [1734028733.435485] [cdc-wdm0/qmi] QMI port
open operation failed: endpoint hangup
ModemManager[13321]: <DEBUG> <dbg> [1734028733.435821] [cdc-wdm0/probe] error
checking QMI support: endpoint hangup
ModemManager[13321]: <DEBUG> <dbg> [1734028733.435881] [cdc-wdm0/probe] port
is not QMI-capable
ModemManager[13321]: <NOTICE> <msg> [1734028733.436181] [cdc-wdm0/probe] probe
step: done
The line containing binary dump with '[cdc-wdm0/at]' faintly suggests, that
port type might be misdetected - but - I have yet to confirm that.
Since the issue was caused by pretty significant refactoring, it may take some
time, but maybe someone can spot the error faster - so I'm reaching out for
help, especially to Dan :-)
Reproducibility is around 50%
Any help would be greatly appreciated.
--
Pozdrawiam/With kind regards,
Lech Perczak
Sr. Software Engineer
Camlin Technologies Poland Limited Sp. z o.o.
Strzegomska 54,
53-611 Wroclaw
Tel: (+48) 71 75 000 16
Email: lech.perc...@camlingroup.com
Website: http://www.camlingroup.com
le910c4_qmi_probe_fail.pcap
Description: application/vnd.tcpdump.pcap
